Ghrelin as a promising therapeutic target for co-occurring autism and epilepsy

The Potential Role of Gut Peptide Hormones in Autism Spectrum Disorder

Gut peptide hormones are one group of secretory factors produced from gastrointestinal endocrine cells with potent functions in modulating digestive functions. In recent decades, they have been found across different brain regions, many of which are involved in autism-related social, emotional and cognitive deficits. Clinical studies have revealed possible correlation between those hormones and autism spectrum disorder pathogenesis. In animal models, gut peptide hormones modulate neurodevelopment, synaptic transmission and neural plasticity, explaining their behavioral relevance. This review article will summarize major findings from both clinical and basic research showing the role of gut peptide hormones in mediating autism-related neurological functions, and their potential implications in autism pathogenesis. The pharmaceutical value of gut hormones in alleviating autism-associated behavioral syndromes will be discussed to provide new insights for future drug development.

Ghrelin suppresses proliferation of fetal neural progenitor cells, and induces their differentiation into neurons

Although considerable progress has been made in understanding how the temporal and regional control of neural progenitor cells (NPCs) dictates their fate, their key regulators during neural development are still unknown. Ghrelin, which is isolated from porcine stomach extract, is an endogenous ligand for the growth hormone secretagogue receptor (GHS-R). The widespread expression of ghrelin and GHS-R in the central nervous system during development suggests that ghrelin may be involved in developmental neural growth. However, its role in regulating fetal NPCs is still unclear. In this study, we investigated the effects of ghrelin on primary cultured NPCs derived from fetal mouse telencephalon. The expressions of both ghrelin and its receptor were observed in NPCs using RT-PCR, immunoblotting and immunocytostaining. Interestingly, the exposure of fetal NPCs to ghrelin at concentrations of 10(-7) and 10(-9)M suppressed their proliferation, and caused them to differentiate into neurons and to extend neurites. These results strongly suggest that ghrelin plays an autocrine modulatory role in fetal neural development.

Targeting of glycine site on NMDA receptor as a possible new strategy for autism treatment

The exact pathophysiology of the neurodevelopment disorder of autism is not clear and there is not any curative approach for it. There is only one FDA-approved medication for its management. Therefore, providing of novel treatments is highly required. The hypofunction of GABAergic system and glutamate toxicity are generally believed to have a causal role for autism. The antagonist of the N-methyl-D-aspartic acid (NMDA) glutamate receptor improves autism. Glycine is required for the activation of NMDA receptor. The antagonist of glycine site decreases NMDA receptor conductance. It is hypothesis that glycine site antagonists can be tested as a new strategy for the management of autism.